This invention relates to an apparatus for producing a cooling or lubricating spray. More particularly, this invention relates to an apparatus of producing a cooling and lubricating spray for cooling and lubricating opposed, reversing shear blades of the type that are used to sever a stream of molten glass in a glass manufacturing installation to form a series of individual gobs from each such glass stream, each of the gobs being adapted to be formed into a hollow container or other useful article.
U.S. Pat. No. 5,573,570 (Leidy, et al.), which is assigned to the assignee of this application, the disclosure of which is incorporated herein by reference, describes a shearing apparatus in which opposed sets of blades are periodically brought into and out of contact with one another to shear a stream of molten glass that passes between each of an opposed pair of blades in each set into individual gobs for further processing. The blades of the aforesaid ""570 patent move along parallel, rectilinear paths, which is the preferred arrangement for modern glass container forming machines of the individual section (I.S.) type when they are used to simultaneously form three or four glass containers at each machine section. It is also known, for example, from U.S. Pat. No. 2,754,627 (Denman), the disclosure of which is also incorporated by reference herein, that opposed glass shear blades can be swung along arcs into and out of shearing engagement with one another.
It is also known, for example, from the aforesaid ""627 patent that it is desirable to spray the shear blades of the glass shear apparatus to cool and lubricate such shear blades. U.S. Pat. No. 4,409,014 (Taylor, et al.), the disclosure of which is also incorporated by reference herein, discloses a specific apparatus for producing an oil-water mixture for use in spraying the blades of a glass stream shearing apparatus that is used to shear each of one or more streams of glass into a series of individual gobs. The shearing of a glass stream into gobs by an opposed pair of blades that are periodically brought into and out of contact with one another is also disclosed in U.S. Pat. No. 4,391,620 (Geisel).
As is recognized in the prior art, the coolant that is applied to the exterior of glass shear blades is often done as a spray through spraying nozzles or spray heads. This is disclosed, for example, in the aforesaid ""014 and ""620 patents. A problem exists with respect to certain prior art glass shear blade cooling Installations, however, in that the spray nozzles, which have very small diameter coolant flow passages, tend to clog with coagulated coolant over an extended period of time. To overcome this problem, such installations are often operated at higher than required coolant pressure, which leads to coolant flow rates that are higher than required for proper blade cooling and lubrication. It is towards a solution to the glass shear blade coolant nozzle clogging problem, to thereby permit a reduction in coolant pressure and flow rates, that the present Invention is directed.
The aforesaid and other problems associated with prior art molten glass shear blade coolant Installations are overcome by the present invention in which the coolant is normally sprayed through spray nozzles at a first, lower pressure, which only need be sufficient to deliver a satisfactory spray volume when it can be assumed that the nozzles are operating in an unclogged or substantially unclogged condition. Periodically, however, the nozzles are purged by temporarily increasing the pressure of the coolant that is sprayed therethrough. This is done by intermittently operating a rodless pneumatic cylinder in which one side of a free piston in a cylinder is intermittently exposed to high pressure air and the other side of the piston is exposed to shear blade coolant.
Accordingly, it is an object of the current invention to provide an improved apparatus for providing a cooling or lubricating spray to spray contacting surfaces of an opposed pair of shear blades that are periodically brought into and out of contact with one another. More particularly, it is an object of the present invention to provide an improved apparatus of the aforesaid character that is well suited for spraying an opposed pair of shear blades in shearing apparatus that is used to periodically severe a stream of molten glass into a series of individual gobs of molten glass.